// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_PUBLIC_BROWSER_BROWSER_URL_HANDLER_H_
#define CONTENT_PUBLIC_BROWSER_BROWSER_URL_HANDLER_H_

#include "content/common/content_export.h"

class GURL;

namespace content {
class BrowserContext;

// We handle some special browser-level URLs (like "about:version")
// before they're handed to a renderer.  This lets us do the URL handling
// on the browser side (which has access to more information than the
// renderers do) as well as sidestep the risk of exposing data to
// random web pages (because from the resource loader's perspective, these
// URL schemes don't exist).
// BrowserURLHandler manages the list of all special URLs and manages
// dispatching the URL handling to registered handlers.
class CONTENT_EXPORT BrowserURLHandler {
public:
    // The type of functions that can process a URL.
    // If a handler handles |url|, it should :
    // - optionally modify |url| to the URL that should be sent to the renderer
    // If the URL is not handled by a handler, it should return false.
    typedef bool (*URLHandler)(GURL* url,
        BrowserContext* browser_context);

    // Returns the null handler for use with |AddHandlerPair()|.
    static URLHandler null_handler();

    // Returns the singleton instance.
    static BrowserURLHandler* GetInstance();

    // RewriteURLIfNecessary gives all registered URLHandlers a shot at processing
    // the given URL, and modifies it in place.
    // If the original URL needs to be adjusted if the modified URL is redirected,
    // this function sets |reverse_on_redirect| to true.
    virtual void RewriteURLIfNecessary(GURL* url,
        BrowserContext* browser_context,
        bool* reverse_on_redirect)
        = 0;

    // Set the specified handler as a preliminary fixup phase to be done before
    // rewriting.  This allows minor cleanup for the URL without having it affect
    // the virtual URL.
    virtual void SetFixupHandler(URLHandler handler) = 0;

    // Add the specified handler pair to the list of URL handlers.
    //
    // Note that normally, the reverse handler is only used if the modified URL is
    // not modified, e.g., by adding a hash fragment. To support this behavior,
    // register the forward and reverse handlers separately, each with a
    // null_handler() for the opposite direction.
    virtual void AddHandlerPair(URLHandler handler,
        URLHandler reverse_handler)
        = 0;

protected:
    virtual ~BrowserURLHandler() { }
};

} // namespace content

#endif // CONTENT_PUBLIC_BROWSER_BROWSER_URL_HANDLER_H_
